The Berlin Philharmonic Orchestra dedicated its new, though not quite finished, $86.4 million chamber music hall this week as part of the city's 750th anniversary celebration. The hall--designed by architect Edgar Wisniewski--is situated near the Berlin Wall. Mayor Eberhard Diepgen and West German Chancellor Helmut Kohl were among the 1,189 guests who watched Philharmonic director Herbert von Karajan and violin soloist Anne-Sophie Mutter perform Vivaldi's "The Four Seasons." Concerts will be played in the hall until Nov. 8 to fine tune the acoustics. Workers will then return to put the finishing touches on the building, which is scheduled to reopen in April.